I can't buy bank stock, or for any practical purposes any financial firm stock (or bonds). I can't buy funds finance-focused mutual funds or any kind. I can't buy stocks of any firm where I have any sort of insider trading, such as contractors.
Lastly, there's a window around FOMC meetings where anyone with any sort of insider knowledge is prohibited to trade at all.
But last I checked on my Robinhood account, I do own some GitLab, Cloudflare, etc. firms that I think are doing quite well compared to their current market prices. And that's mostly based on what I read (HN, etc).
The question is, should employees be disallowed to own stocks at all? (Right now this rule is aimed at officers, but officers are like 20% of the number of employees of my division, so it's still a lot). I would say doing so makes it quite more difficult for economists to take jobs at the Fed, where the salary is not as competitive as in other places such as the private sector (and already all the friends in my PhD Finance cohort earn more than I do..). To make a parallel, imagine that working at Google prohibits you from owning stocks at any firm that trades/buys/sells/interacts with Google or its competitors.